Method of and means for testing the moisture content of grain and other compressible materials



Oct. 6, 1959 P. I. LANGMEAD 2,907,203

METHOD OF AND MEANS FOR TESTING THE MOISTURE comm OF GRAINAND 0mm COMPRESSIBLE MATERIALS Filed Dec. 26, 1956 2 Sheets-Sheet 1 FlG.ld

1959 P. LANGMEAD 2,907,203

METHOD OF AND MEANS FOR TESTING THE MOISTURE comm 0F GRAIN AND OTHER COMPRESSIBLE MATERIALS Filed Dec. 26. 1956 2 Sheets-Sheet 2 United States PatentO METHOD OF AND MEANS FOR TESTING THE MOISTURE CONTENT OF GRAIN AND OTHER COMIRESSIBLE MATERIALS Paul I. Langmead, Bishopton, stratford-on-Avon, England Application December 26, 1956, Serial No. 630,674

9 Claims. (Cl. 73-73) This invention relates to a device for testing the moisture content of grain and other compressible materials in which variation in compressibility afiords an indication of the moisture content.

It is known that the hardness of grain and many other compressible materials varies substantially in inverse proportion to the moisturecontent, i.e. the softer the grain or other like material the greater is the amount of moisture present therein.

In the drying of grain it has previously been proposed in order to ensure that the grain delivered from the drier to storage has a moisture content below a predetermined value, periodically to deliver measured supplies of the grain discharging from the drier to mechanical testing means in which each sample is subjected in the form of a confined column to a predetermined pressure applied by a plunger, and to utilise the movement of the plunger permitted by the compression of the grain sample column to actuate means causing diversion of the discharging grain for further drying when the moisture content of the sample exceeds a predetermined maximum and the plunger moves to or beyond a corresponding predetermined point. Apparatus proposed for carrying out this method comprises means for periodically delivering a measured sample, taken from a continuously discharging flow of grain from a grain drier, to a testing device comprising a receiving chamber in which each grain sample is confined in the form of a column, a plunger adapted to be operated to exert a predetermined pressure on the confined column and mechanism actuated on movement of the plunger to or beyond a predetermined point to cause diversion of the continuously discharging grain.

In order to avoid unnecessary repetition the word grain used in the following description and in theappended claims denotes (except when, preceded by the word cereal) not only the seeds of cerealplants such as wheat, rye, barley and oats but also other plant seeds (e.g. clover, vegetable and flower seeds) and other compressible materials, such as foundry sand, sawdust and other fibrous materials the moisture content of which can be tested by the method and device according to the invention.

The object of the invention is to provide a small, compact and readily portable device of simple construction for efficiently and rapidly testing the moisture content of a sample of grain and like materials,-the term like materials used herein meaning materials in which variation is compressibility aiforts an indication of the moisture content.

With the foregoing object in view a device made in accordancewith the invention comprises two members arranged for screwing one on the other, one member being formed with a chamber or recess to receive the sample of grain or like material to be tested and the other member being fitted with aspring pressed plunger adapted on screwing the two members together to press on the grain orthe like in the chamber until the spring is compressed as far as possible whereby the reduction in volume of the grain in the recess, which reduction in volume corresponds to the moisture content, can be measured to indicate the moisture content of the grain The device may comprise two cylindrical members one being formed with a recess to receive the grain to betested, and the other having slidably mounted therein a spring pressed plunger, said members being formed with complementary right-handed screw threads whereby they can be screwed on to one another with the spring pressed plunger in one member in alignment with the recess in the other member, to force the plunger on to the grain in the recess and compress the spring by reason of the resistance offered by the grain, which resistance is inversely proportional to the moisture content thereof, whereby the relative axial movement of the two members to effect complete compression of the spring is proportional to and can be utilised to give a measurement of the moisture content of the grain under test.

In the accompanying drawings which illustrate one form of device for carrying the present invention into effect:

Figs. 1, la, 1b, 1c and 1d, illustrate respectively the various separate parts of the device.

Fig. 2 is an elevation, and Fig. 3 is a vertical section of the device showing the various parts assembled and in the relative positions corresponding to the completion of a test.

Figs. 4 and 4a are respectively views in plan and elevation of a tool for operating the device and Fig. .5 illustrates a modified construction.

The device shown in the drawings comprises upper and lower cylindrical parts 10 and 11 formed respectively with inner and outer screw threads 12, 13 whereby the part 10 can be screwed on to the part 11.

The part 10 is closed at top and open at the bottom and its wall is cut away at three dilferent places to form three rectangular openings 14 separated by relatively narrow wall strips 15. Each of these wall strips 15 has a tapped aperture 16, the three apertures 16 being disposed at difierent levels. These three apertures can be selectively engaged by a screw 17 for the purpose hereafter described. The closed top of the part 10 is formed with a milled periphery and the lower surface thereof is formed integral with, or has fixed thereto, a hub or bush 19 which is centrally disposed on the closed top and projects downwards therefrom. The central passage in the hub or bush 19 is an extension of, or is disposed in alignment with a centrally disposed aperture 20 in the closed top. Slid ably mounted in this central passage is the rod 21 of a piston-like plunger 22 normally urged away from the lower end of the bush by a coiled spring 23 mounted externally on the bush and bearing at one end against the closed top of the part 10 and at the other end against the piston-like plunger 22. The rod 21 is retained in the bush, in which it is capable of limited sliding movement, by a radial pin 24 fixed in the bush so as to engage in a reduced part 25 of the piston rod. When not in use the end of the plunger rod 21 remote from the piston is flush with the top surface of the part 10 and is held in this position by the pin 24 bearing against the shoulder formed by reducing the part 25.

The part 11 is made from a solid workpiece and has formed in each of the opposite ends thereof a cylindrical recess 26 or 27. The recess 26 forms a chamber to receive a sample of the grain 28 to be tested. The recess 27 is provided merely to reduce the weight of the part. The part 11 is formed with an end flange 29 of enlarged diameter having a milled periphery, and with an axial extension 11 of reduced diameter projecting beyond the screw thread 13 (which is right handed) and this axial extension is provided with a coarse external left-hand screw thread having a pitch of about three times the pitch of the thread 13. A collar 30 formed with an internal thread which is complementary to the left-hand thread is screwed on to the axial extension 11 The outerwall of the collar 30 is formed with a longitudinally extending groove 31, one side edge of which (see Fig. 1c) extends a little beyond the other side edge so that when the part is screwed down on to the part 11 the inner end of the screw 17 will butt against the extending side edge and will thereby become engaged in the groove. The outer wall of the collar 30 also has engraved or otherwise formed thereon a calibrated scale 32 and at least one edge of one of the wall strips has engraved or otherwise formedthereon an arrow or like indicator 15 which is adapted to co-operate with the calibrated scale 32 as hereafter more fully described.

The device described and illustrated in the drawings is used in the following manner.

The part 10 and collar 30 are unscrewed and removed from the part 11 and the recess 26 in the latter is filled evenly with the grain for example a cereal grain to be tested up to the rim, the bottom of the recess being occasionally tapped during filling to ensure firm and level filling thereof. It is important in order to obtain a correct reading that the recess should contain a firm and level filling and this may be checked by using a fiat surface, for example, of a ruler. The collar 30 is now screwed back tight on to the extension 11 and the part 10 is screwed on the part 11. When screwing the part 10 on to the part 11 the plunger 22, which is a smooth sliding fit in the recess, presses down on to the grain. If the grain under test is dry it will offer relatively big resistance to the downward pressure of the plunger and the spring 23 will be completely compressed (as shown in Figs. 2 and 3) after a relatively small relative axial movement of the parts 10, 11 and of the plunger 22. If the grain has a big moisture content the relative axial movement of the parts 10, 11 and of the plunger will be correspondingly greater. During the screwing down operation the end of the screw 17 will as above described engage in the groove 31 in the collar so that the latter, by reason of the left-hand screw engagement, will also turn with the part 10 on the part 11 and will thereby progressively move axially into the part 10 until the spring 23 is fully compressed, whereupon no further relative rotation between the paits 10 and 11 is possible. The extent of axial movement of the collar 30 into the part 10 will therefore depend on the extent of the relative axial movement between the parts 10 and 11 which is necessary to compress the spring fully, and this will depend on the resistance opposed by the grain, which resistance will in turn depend on the moisture content thereof. By suitably calibrating the scale 32, therefore, the pointer 15 will indicate on the completion of the test the extent of relative axial movement of the parts 10, 11 and therefore the moisture content of the grain.

Fig. 3 illustrates the relative positions of the parts on the completion of a test. The grain tested was in this case quite dry and it was not possible by reason of the high resistance of the grain for the plunger to enter the recess 26. The arrow 15 therefore points to the part of the calibrated scale denoting minimum moisture in the sample tested.

in practice the scale 32 will be calibrated difierently for diilerent varieties, or groups of varieties, of grain, and different collars 30 having difierently calibrated scales may be provided for the different Varieties of grain to be tested. All three wall strips 15 may have a tapered side carrying an arrow or like pointer 15 The device may be operated by hand but in order to facilitate operation the opposite ends of the parts 10 and 11 may be formed or adapted for arrangement by a turning tool, a suitable form of which is shown in Figs. 4 and 4a. As shown, the end of each part 10, 1 1 is pro- 4 vided with three equiangularly spaced recesses 33 adapted to be engaged respectively by three pins or studs 34 carried respectively on a tool such as 35, so that the turning of these parts 10, 11 is facilitated by a lever action. The tool shown is also formed with a central aperture 36 to receive the plunger rod 21 which will project through the end of the part 10 'when the latter is screwed down on to the part 11.

The device described and illustrated in the drawings may be modified in many ways without departing from the scope of the invention. For example, the axial extension 11 of the parts 11 and the collar 30 may be eliminated and the end of the plunger-rod which projects more or less fromthe part 10 on completing a test may be calibrated to indicate the moisture content which will correspond with the amount of projection of the rod on completion of a test. Alternatively the side edges of the openings 14 may be suitably calibrated and these calibrations read against the top of the cylindrical recess containing the grain. In the latter case diiferent calibrations can be made for difierent kinds of grain, the natural hardnesses of which are different. For example, one side edge could be suitably calibrated for wheat, another side edge could be suitably calibrated for barley, and another for oats.

One embodiment of the alternative modification above referred to is illustrated diagrammatically in Fig. 5 of the accompanying drawings. The construction shown in this figure is of generally similar construction to that shown in Figs. 1-3 but the axial extension 11 and collar 30 are eliminated. A plate 40 is fixed to the side edge of one wall strip 15 and carries a vertical scale 41 calibrated in units 1-9, and the wall of the recess 26 is formed with a scale 42 calibrated in units 0-9 each unit also being calibrated in sub-units and extending around the whole periphery of the rim. The flange 10 of the part 10 is slotted or notched, one edge 10 of the notch forming an indicator co-operating with the scale 42. The top edge 11 of the part 11 also constitutes an indicator co-operating with the vertical scale 41. In operation the scales 41, 42 will move relatively to each other as the parts 10, 11 are screwed together, the relative axial movement between these two parts for one full rotation of the part 10 on the part 11 corresponding to one unit of the scale 41. Each unit on the scale 42 will indicate of a revolution. In the relative positions of the parts shown in Fig. 5 a test has been completed and the reading on completion of the test is 4.8. This reading corresponds to the moisture content of the grain tested and is interpreted accordingly by the user.

In many cases it will only be required to provide four calibration marks to provide four corresponding approximate indications of moisture content, for example, in the case of a cereal grain:

(1) Fit for storage up to four weeks from harvest (moisture up to 17% to 18% above which artificial drying would be essential).

(2) Fit for storage until February after harvest (moisture up to said 16 /2 (3) Fit for storage until April after harvest (moisture up to say 15%).

(4) Fit for long-term bulk storage (moisture up to 14% The device can even be used without any calibrations the approximate moisture content being estimated from the condition of the grain after compression. Thus, in the case of a cereal grain, if the grain remains in a lump it is not fit for combine harvesting without artificial drying; if it tends to cling in the chamber the moisture content will generally fall within 2 or 3 above.

The device can be made of any suitable material, preferably a light weight material; the particular construction above described is made of metal.

The invention provides a simple method and a readily portable manually operated device for efficiently and rapidly testing the moisture content of suitable materials.

I claim:

1. A device for testing the moisture content of grain and like materials comprising two members arranged for screwing one on the other, one member being formed with a chamber or recess to receive the sample of grain or like material to be tested, a compression spring pressed plunger slidably mounted within the other member adapted on screwing the two members together to press on the grain or the like in the chamber until the spring is compressed to the limit of its resiliency, the spring having a known resiliency, whereby the reduction in volume of the grain in the recess, which reduction in volume corresponds to the moisture content, can be measured to indicate the moisture content of the grain.

2. A device according to claim 1 wherein the plunger carrying member is provided with a longitudinally extending calibrated scale co-operating with the top of the chamber to indicate the relative axial movement between the chamber and plunger carrying member and therefore the diminution in volume of the grain.

3. A device according to claim 2 wherein the chamber is formed on its outer periphery with a calibrated scale cooperating with an indicator carried on the plunger carrying member to indicate fractional parts of a complete relative turn between the chamber and the plunger carrying member.

4. A device according to claim 1 wherein means are provided for measuring the relative axial movement between the chamber and the plunger carrying member during compression of the spring in order to measure the reduction in volume of the grain in the chamber and thereby indicate the moisture content of the grain.

5. A device according to claim 4 wherein the means referred to comprise a collar screwed by means of a lefthand screw thread on to the chamber and arranged to be rotated by and with the said member when the latter is screwed right-handedly on to the chamber, a calibrated scale carried on the collar and co-operating with an indicating mark on the said member to indicate the extent of axial movement of the collar produced by the rotation of the member.

6. A device for testing the moisture content of grain and like materials comprising two cylindrical members one being formed with a recess to receive the grain to be tested,

and the other having slidably mounted therein a stem carried plunger, a coiled compression spring of known resiliency on the plunger stem bearing against the member, said members being formed with complementary right-handed screw threads whereby they can be screwed on to one another with the spring pressed plunger in one member in alignment with the recess in the other member, to force the plunger on to the grain in the recess and compress the spring by reason of the resistance oflered by the grain, which resistance is inversely proportional to the moisture content thereof, whereby the relative axial movement of the two members to eifect complete compression of the spring is proportional to and can be utilised to give a measurement of the moisture content of the grain under test.

7. A device according to claim 6 further comprising a collar having a left-hand screw engagement with the member containing the recess and adapted to be rotated by the member containing the spring pressed plunger when the parts are screwed together, whereby the collar is moved axially in accordance with the relative axial movement of the two cylindrical members, and means for indicating the extent of this axial movement when the spring has been completely compressed and consequently the moisture content of the grain under test.

8. A device according to claim 7 wherein the indicating means comprise an axially disposed calibrated scale on the collar and a pointer or indicator carried on the member containing the spring pressed plunger and co operating with the calibrated scale.

9. A device according to claim 7 wherein the operating connection between the collar and the member containing the spring pressed plunger comprises an inwardly directed projection carried on the wall of the said member and an axially directed groove in the Wall of the collar arranged to be engaged by the said projection when the member carrying the latter is screwed on to the member containing the recess for the grain.

References Cited in the file of this patent UNITED STATES PATENTS 1,952,523 Abbott Mar. 27, 1934 2,082,364 Store June-1, 1937 2,365,496 Shaw Dec. 19, 1944 2,544,943 Wilty Mar. 13, 1951 

